Stamped and formed electrical contact

ABSTRACT

An electrical contact portion having a box portion about a central axis and joined together along a seam by a mechanical interlocking portion, the contact being characterized in that a port is formed in a wall of the box to provide access by a support member to the interior of the box in order to support the seam at the interlocking portion during forming. An electrical contact having a contact portion with a contact arm between forwardly extending walls for receiving and engaging a mating terminal (not shown), where the contact portion includes a retention shoulder disposed over a contact arm that is engageable to retain the contact within a connector housing, characterized in that the retention shoulder is a rear edge of a tab formed integrally and folded over from one of the sides, a portion of which is partially separated therefrom along a slit and pressed inward so that the tab is moved closer to the opposing wall.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to electrical terminals and, in particular, toelectrical terminals having a contact portion formed from a single blankof material.

2. Summary of the Prior Art

It is known in the industry to form electrical contacts from a singleblank of material. When these contacts include a enclosed box portion,there is at least one seam that must be joined together to maintain thestructural integrity of the box. One way of accomplishing this is tolaser weld a number of places along the box. A problem with this is thatlaser welding is relatively slow in relation to the stamping and formingprocesses being applied to the manufacture of the contact. Anotherproblem is that the laser welding equipment involves a large capitalexpense. Therefore, it has been discovered that it is possible to jointhe seam together by way of interlocking mechanical features formedtherealong. These features may take on the form of a dove-tail typejoint or the rounded meandering similar to the keys on pieces of ajigsaw puzzle.

In order to join the complementary mechanical features together alongthe seam, it is necessary to support the walls which incorporate thesemechanical features from the inside of the box portion. This istypically accomplished by inserting a support member into either of theopen ends about which the box shell has been formed. A problem with thisexists where the simultaneous stamping and forming processes result incontact structure that blocks the ends of the box or the structure isnot sufficiently large that a robust pin may be inserted therein.Therefore, what is necessary is to provide support to the underside ofthe seams corresponding to the mechanical interlocking portions withoutneeding access through the open ends of the box portion.

Another problem that occurs in stamping and forming a single blank ofmaterial to form a contact portion of an electrical terminal is that itis necessary in some designs to have certain features overlie anotherfeature. This is typically accomplished by the design layout of theblank of material. However, in some cases it is impossible to form thedesired feature in such a way that it overlaps the other component. Whatis needed is a way to overlie one component with another feature of aone piece contact.

SUMMARY OF THE INVENTION

It is an object of this invention to provide access to the underside ofthe interlocking portion of the seam of a contact box portion formedabout axis 1, so that the seam may be supported during formation of thebox to assure that the contact box walls are interlocked.

This object is accomplished by providing an access port in a wall of thecontact box portion which enables a support member to be disposedbeneath the interlocking portion of the seam of the box.

It is another object to provide a feature that overlies anothercomponent of the contact.

This object is accomplished by providing a slit along the contact thatenables the material on one side of the slit to be offset relative tothe material on the other side of the slit, thereby enabling a featureattached to the offset side of the slit to be moved over another part ofthe contact.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an electrical contact according to the presentinvention;

FIG. 2 is a top view of the electrical contact of FIG. 1;

FIG. 3 is a cut-away top view taken along line 3--3 of the electricalcontact of FIG. 1; and

FIG. 4 is a sectional view of the assembly of the box of the terminal ofFIG. 1 taken at line 4--4 of FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference first to FIG. 1, an electrical contact according to thepresent invention is shown generally at 2. The contact 2 includes aconductor engaging portion 4 advantageously shown to be crimpable upon awire lead. The conductor engaging portion 4 may take on other forms asdesired. The conductor engaging portion 4 is interconnected, by anintermediate portion 6, to the contact portion 8 that is adapted toreceive a tab or pin terminal (not shown) therein.

The contact portion 8 includes a box section 10 formed of a top 12, abottom 14, and side walls 16 and 18 (FIG. 2). The box section 10 isillustrated as a rectangular shell portion having a hollow interior. Itwould also be possible to have a cylindrical box section or a boxsection of another desirable form. The invention is not intended to belimited to a rectangular form.

Furthermore, the contact box section 10 includes an end flap 20 thatacts to separate the functions of the contact portion 8 from theintermediate portion 6 and conductor engaging portion 4 by preventingover-insertion of a pin into the contact portion, over insertion of thewire lead (not shown) inserted into the conductor engaging portion 4, orto prevent by-products of soldering a lead to the conductor engagingportions 4 from entering the contact portion 8. The end flap 20 isfolded downward from the top 12 or upward from the bottom 14 to blockentrance to the rear open end of the box section 10.

Opposite the end flap 20 is pin receiving portion 22 at the front end 24of the contact portion 8. The pin receiving portion 22 is supported bythe top 12 and bottom 14 of the box section 10. Extending forwardly fromthe sides 16,18 of the box portion, are cantilevered contact arms 26that extend forwardly to a free end 28. The free end 28 is supported bya tongue 30 formed by a portion of the end receiving portion 22, bestseen in FIG. 3.

In order to provide contact retention within a connector housing, it iscommon to form a shoulder which can be engaged by part of the connectorhousing or a secondary locking member cooperating therewith. In somecases it is necessary that the shoulder be formed on the same side ofthe contact as the contact arms, such as in this case. It is alsooccasionally necessary that the shoulder exist over the contact arms. Inorder to accomplish this, tabs 32 are formed in each of the top andbottom walls 12,14. These tabs 32 are then folded over into the openpart of side walls 16,18. However, due to the flat sheet layout of thecontact blank (not shown), there is a significant gap between facingtabs 32. In order to reduce the gap 34 between the tabs 32, such thatrearward edges 36 of each of the tabs combine to form a shoulder surfaceengageable by some part of the connector housing, slits 38 are formed inthe extensions of the bottom and top walls 14,12. Portions 39 of thewall on one side of the slits are then displaced inwards toward eachother such that the gap 34 is reduced while leaving the portions 39 aunitary part of the walls from which they are formed, therebyeliminating sharp edges and corners which may lead to assembly oroperational difficulties. In the illustrative example shown in thedrawings, tabs 32 overlie a contact arm 26 to form a shoulder. It wouldalso be possible to have the tabs underlie a feature depending on thedesired outcome.

With reference now to FIG. 2 and FIG. 3, in order to provide thestructural integrity necessary to generate the proper contacting forceon a mating contact and to assure rigidity to the contact 2 duringassembly, it is necessary to join the side edges of the single blank ofmaterial used together along seam 40. Seam 40 includes an interlockingportion 42. This interlocking portion 42 is a meandering profile similarto that of a jigsaw puzzle that, once opposing profiles 42a 42b areinterlocked, prevents separation of the seam 40. In order to providesupport to the interlocking portion 42 during the forming process, aport 44 is formed in one of the box section 10 walls. In thisembodiment, the port 44 has advantageously been formed in the oppositebottom wall 14. It would be possible to incorporate the port into otherwalls if desired.

With reference now to FIG. 4, the port 44 formed in the bottom 14 of thebox section 10 is made large enough to receive a support member 46therethrough. The support member 46 extends into the open portion of thebox 47 to a point just below where it is desired to have the top wall 12formed. The top wall 12 is made up of two wall segments 12a,12b.Typically, one of the wall segments would be brought down against thesupport member 46 by a forming member 48 slightly before its counterpartwall segment 12a, such that opposing profiles 42a, 42b, are theinterlocking portion 42 of the seam 40 may interlock with each other.Once the interlocking portion 42 of the seam 40 is closed, the supportmember 46 may be removed from the port 44 and the box-section 10 of thecontact 2 will maintain its structural integrity.

Advantageously, the present invention provides for joining the seam ofan electrical contact box portion by mechanical means where it is notpossible to insert a support member longitudinally through the box. Itis another advantage of this invention, that by joining the seammechanically, the contact may be produced in an economical efficientmanner. It is an advantage of forming the slits in the contact walls,whereby a feature may be brought over a corresponding feature, in orderto save material required to manufacture a particular contact. It isimportant to note that while this invention is being described asoverlying a portion of the contact, it could just as easily apply tounderlying a portion of the contact.

We claim:
 1. An electrical contact portion, comprising a box portionformed about a central axis and joined together along a seam bymechanical interlocking portions to produce a shell-like structure withan hollow interior, the contact portion being characterized in that aport is formed in a wall of the box that is opposite the seam to provideaccess for a support member to the interior of the box transverse to thecentral axis in order to properly seal the interlocking portions duringforming.
 2. The electrical contact portion of claim 1, furthercharacterized in that the port is disposed directly opposite theinterlocking portions of the seam.
 3. The electrical contact portion ofclaim 1 or claim 2, further characterized in that the box has four sideswith the interlocking portions of the seam disposed centrally within oneof the sides.
 4. The electrical connector portion of claim 1, furthercharacterized in that the interlocking portions include a meander.
 5. Amethod of forming an electrical contact comprising the steps offorming aflat contact blank having a port therein and mechanical interlockingfeatures therealong; folding the flat contact bank into a box shape andinserting a support member through the port into the box shape in orderto support the interlocking features as the box is closed and thefeatures are joined together.
 6. An electrical contact comprising acontact portion for receiving and engaging a mating terminal andincluding a contact arm disposed between two opposing walls, there thecontact portion further includes a retention shoulder for retaining thecontact within a connector housing, characterized in that one of theopposing walls includes a wall portion from which an integrally formedtab extends and is folded-over towards the other one of the opposingwalls where the retention shoulder is a rear edge of the tab, theportion of the wall being partially separated from the wall along a slitwhile remaining joined to the wall at opposite ends where the wallportion is pressed inward so that the tab is moved closer the opposingwall.
 7. The electrical contact of claim 6, further characterized inthat the contact portion includes a second tab extending in a similarfashion as the other tab from the other wall brought towards each other.8. The electrical contact of claim 6 or claim 7, further characterizedin that the contact portion includes two pairs of tabs forming twoseparate shoulders.
 9. The electrical contact of claim 6, furthercharacterized in that the tabs overlie the contact arm.
 10. Theelectrical contact of claim 6, further characterized in that a boxshaped pin receiving portion is at a forward end of the contact.